Math, asked by oneworldd20021, 1 month ago

the speed of stream of river is 3 km/hrs A boat goes 30km downstream and return back and take 30 min less time then upstream . find the speed of boat in still water.​

Answers

Answered by Anonymous
2

Answer:

Answer

Given :

Speed of boat in still water =15 km/hr

Let x be speed of the stream in km/hr

Speed of the boat upstream =15−x

Speed of the boat down stream =15+x

Time taken for upstream T

1

=

15−x

30

Time taken for downstream T

2

=

15+x

30

Given, T

1

+T

2

=

2

9

=

15−x

30

+

15+x

30

=

2

9

=30(

15−x

1

+

15+x

1

)=

2

9

=30(

(15−x)(15+x)

15+x÷15−x

)=

2

9

=

225−x

2

30×30

=

2

9

=

225−x

2

100

=

2

1

⇒225−x

2

=200

⇒x

2

=25

⇒x=5 ....(∵x is +ve)

⇒x=5 km/hr

Speed of the stream =5 km/hr.

Step-by-step explanation:

hope it will be helpful to you dear friend

Answered by Anonymous
0

Answer:

12

Step-by-step explanation:

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